Igniter cable conduit for gas turbine engine

ABSTRACT

A cable conduit may comprise a head end, a sleeve having a foot end, a boot, and a split grommet having a first upper surface, wherein the head end is coupled to the sleeve opposite the foot end, wherein the boot comprises a first flange and is coupled to the foot end, wherein the head end comprises a second flange having a second upper surface and a cutout penetrating into an interior volume of the sleeve, and wherein the split grommet is coupled about the inner diameter of the cutout.

FIELD

The disclosure relates generally to protective structures for cables andcable pathways in gas turbine engines.

BACKGROUND

Gas turbine engine cables may pass directly through a bypass duct of agas turbine engine and be exposed to engine bypass flow. The bypass flowenvironment is a harsh environment tending to damage or degrade cableperformance over time and may expose the cable to impact with objectstransported in the bypass flow.

SUMMARY

In various embodiments the present disclosure provides a cable conduitcomprising a head end, a sleeve having a foot end, a boot, and a splitgrommet having a first upper surface, wherein the head end is coupled tothe sleeve opposite the foot end, wherein the boot comprises a firstflange and is coupled to the foot end, wherein the head end comprises asecond flange having a second upper surface and a cutout penetratinginto an interior volume of the sleeve, and wherein the split grommet iscoupled about the inner diameter of the cutout.

In various embodiments, the cable conduit further comprises a forwardsection and an aft section. In various embodiments, the forward sectioncomprises a first perforation through a forward aerodynamic surface andthe aft section comprises a second perforation through an aftaerodynamic surface, wherein the first perforation and the secondperforation are in fluid communication with the interior volume of thesleeve, wherein a portion of a bypass flow passes through the firstperforation into the interior volume and exits the interior volumethrough the second perforation. In various embodiments, the bootcomprises a circumferential channel. In various embodiments, the forwardsection further comprises forward sleeve having a first distal end andthe aft section further comprises an aft sleeve having a second distalend, wherein the first distal end and the second distal end are disposedwithin the circumferential channel. In various embodiments, the boottends to allow the forward section and the aft section to translate inresponse to a differential thermal growth between an outer case and acombustor case. In various embodiments, the sleeve comprises a sleevelocking feature. In various embodiments, the split grommet comprises amating surface comprising at least one of an extrusion, a finger, acavity, a pocket, a bore, or an embedded stud. In various embodiments,the second flange is coupled at the second upper surface to the outercase and the first flange is coupled to the combustor case. In variousembodiments, the sleeve comprises at least one of a circular crosssection, an elliptical cross section, an oblate cross section, anangular cross section, a teardrop cross section, or an airfoil crosssection.

In various embodiments, the present disclosure provides a gas turbineengine comprising a compressor section configured to compress a gas, acombustor section aft of the compressor section and configured tocombust the gas, a fan section configured to produce a bypass flow, anouter case having an inner surface and an inner case having an outersurface defining a bypass flow duct there between, and a cable conduit,disposed within the bypass flow duct, comprising: a head end, a sleevehaving a foot end, a boot, and a split grommet having a first uppersurface, wherein the head end is coupled to the sleeve opposite the footend, wherein the boot comprises a first flange and is coupled to thefoot end, wherein the head end comprises a second flange having a secondupper surface and a cutout penetrating into an interior volume of thesleeve, wherein the split grommet is coupled about the inner diameter ofthe cutout, and wherein the second flange is coupled at the second uppersurface to the inner surface of the outer case and the first flange iscoupled to the outer surface of the inner case.

In various embodiments, the cable conduit further comprises a forwardsection and an aft section. In various embodiments, the forward sectioncomprises a first perforation through a forward aerodynamic surface andthe aft section comprises a second perforation through an aftaerodynamic surface, wherein the first perforation and the secondperforation are in fluid communication with the bypass flow duct and theinterior volume of the sleeve, wherein a portion of the bypass flowpasses through the first perforation into the interior volume and exitsthe interior volume through the second perforation. In variousembodiments, the boot comprises a circumferential channel. In variousembodiments, the forward section further comprises forward sleeve havinga first distal end and the aft section further comprises an aft sleevehaving a second distal end, wherein the first distal end and the seconddistal end are disposed within the circumferential channel. In variousembodiments, the boot tends to allow the forward section and the aftsection to translate in response to a differential thermal growthbetween the outer case and the inner case. In various embodiments, thesleeve comprises a sleeve locking feature. In various embodiments, thesplit grommet comprises a mating surface comprising at least one of anextrusion, a finger, a cavity, a pocket, a bore, or an embedded stud. Invarious embodiments, the sleeve comprises at least one of a circularcross section, an elliptical cross section, an oblate cross section, anangular cross section, a teardrop cross section, or an airfoil crosssection.

In various embodiments, the present disclosure provides a method ofassembling a cable conduit comprising inserting a cable through a bootand coupling the boot to an inner case of a bypass flow duct, insertinga first distal end of a forward section and a second distal end of anaft section of a cable conduit into a mouth of the boot and furtherinserting the first distal end and the second distal end into acircumferential channel of the boot, aligning a first piece and a secondpiece of a split grommet with a collet of the cable and coupling theforward section and the aft section about the cable, locating a forwardflange of the forward section with respect to an outer case of thebypass flow duct, and coupling the cable conduit to the outer case.

The forgoing features and elements may be combined in variouscombinations without exclusivity, unless expressly indicated hereinotherwise. These features and elements as well as the operation of thedisclosed embodiments will become more apparent in light of thefollowing description and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The subject matter of the present disclosure is particularly pointed outand distinctly claimed in the concluding portion of the specification. Amore complete understanding of the present disclosures, however, maybest be obtained by referring to the detailed description and claimswhen considered in connection with the drawing figures, wherein likenumerals denote like elements.

FIG. 1A illustrates an exemplary gas turbine engine;

FIG. 1B illustrates a bypass flow duct having a cable conduit, inaccordance with various embodiments;

FIG. 2 illustrates a cable conduit, in accordance with variousembodiments;

FIG. 3A illustrates a forward section of a cable conduit, in accordancewith various embodiments;

FIG. 3B illustrates an aft section of a cable conduit, in accordancewith various embodiments;

FIG. 4 illustrates a boot of a cable conduit, in accordance with variousembodiments;

FIG. 5 illustrates a split grommet of a cable conduit, in accordancewith various embodiments;

FIG. 6 illustrates a split grommet of a cable conduit, in accordancewith various embodiments;

FIG. 7 illustrates a split grommet of a cable conduit, in accordancewith various embodiments;

FIG. 8 illustrates a split grommet of a cable conduit, in accordancewith various embodiments;

FIG. 9 illustrates a split grommet of a cable conduit, in accordancewith various embodiments;

FIG. 10 illustrates a sleeve of a cable conduit, in accordance withvarious embodiments;

FIG. 11 illustrates a sleeve of a cable conduit, in accordance withvarious embodiments;

FIG. 12A illustrates a bypass flow duct having a cable conduit, inaccordance with various embodiments;

FIG. 12B illustrates a bypass flow duct having a cable conduit, inaccordance with various embodiments;

FIG. 12C illustrates a cable conduit configured to pass through a bypassflow duct, in accordance with various embodiments;

FIG. 12D illustrates a bypass flow duct having a cable conduit, inaccordance with various embodiments;

FIG. 12E illustrates a bypass flow duct having a cable conduit, inaccordance with various embodiments; and

FIG. 13 illustrates a method of assembling a cable conduit, inaccordance with various embodiments.

DETAILED DESCRIPTION

The detailed description of exemplary embodiments herein makes referenceto the accompanying drawings, which show exemplary embodiments by way ofillustration and their best mode. While these exemplary embodiments aredescribed in sufficient detail to enable those skilled in the art topractice the disclosures, it should be understood that other embodimentsmay be realized and that logical, chemical, and mechanical changes maybe made without departing from the spirit and scope of the disclosures.Thus, the detailed description herein is presented for purposes ofillustration only and not of limitation. For example, the steps recitedin any of the method or process descriptions may be executed in anyorder and are not necessarily limited to the order presented.Furthermore, any reference to singular includes plural embodiments, andany reference to more than one component or step may include a singularembodiment or step. Also, any reference to attached, fixed, connected orthe like may include permanent, removable, temporary, partial, fulland/or any other possible attachment option. Additionally, any referenceto without contact (or similar phrases) may also include reduced contactor minimal contact.

In various embodiments and with reference to FIG. 1A, a gas turbineengine 20 is provided. Gas turbine engine 20 may be a two-spool turbofanthat generally incorporates a fan section 22, a compressor section 24, acombustor section 26 and a turbine section 28. Alternative engines mayinclude, for example, an augmenter section among other systems orfeatures. In operation, fan section 22 can drive air along a bypassflow-path B while compressor section 24 can drive air for compressionand communication into combustor section 26 then expansion throughturbine section 28. Although depicted as a turbofan gas turbine engine20 herein, it should be understood that the concepts described hereinare not limited to use with turbofans as the teachings may be applied toother types of turbine engines including three-spool architectures.

Gas turbine engine 20 may generally comprise a low speed spool 30 and ahigh speed spool 32 mounted for rotation about an engine centrallongitudinal axis A-A′ relative to an engine static structure 36 via oneor more bearing systems, shown as 38, 38-1, and 38-2 in FIG. 1A. Itshould be understood that various bearing systems at various locationsmay alternatively or additionally be provided to bearing system 38,bearing system 38-1, and bearing system 38-2.

Low speed spool 30 may generally comprise an inner shaft 40 thatinterconnects a fan 42, a low pressure (or first) compressor section 44(also referred to a low pressure compressor) and a low pressure (orfirst) turbine section 46. Inner shaft 40 may be connected to fan 42through a geared architecture 48 that can drive fan 42 at a lower speedthan low speed spool 30. Geared architecture 48 may comprise a gearassembly 60 enclosed within a gear housing 62. Gear assembly 60 couplesinner shaft 40 to a rotating fan structure. High speed spool 32 maycomprise an outer shaft 50 that interconnects a high pressure compressor(“HPC”) 52 (e.g., a second compressor section) and high pressure (orsecond) turbine section 54. A combustor 56 may be located between HPC 52and high pressure turbine 54. A mid-turbine frame 57 of engine staticstructure 36 may be located generally between high pressure turbine 54and low pressure turbine 46. Mid-turbine frame 57 may support one ormore bearing systems 38 in turbine section 28. Inner shaft 40 and outershaft 50 may be concentric and rotate via bearing systems 38 about theengine central longitudinal axis A-A′, which is collinear with theirlongitudinal axes. As used herein, a “high pressure” compressor orturbine experiences a higher pressure than a corresponding “lowpressure” compressor or turbine.

The core airflow C may be compressed by low pressure compressor 44 thenHPC 52, mixed and burned with fuel in combustor 56, then expanded overhigh pressure turbine 54 and low pressure turbine 46. Mid-turbine frame57 includes airfoils 59 which are in the core airflow path. Low pressureturbine 46, and high pressure turbine 54 rotationally drive therespective low speed spool 30 and high speed spool 32 in response to theexpansion.

Gas turbine engine 20 may be, for example, a high-bypass geared aircraftengine. In various embodiments, the bypass ratio of gas turbine engine20 may be greater than about six (6). In various embodiments, the bypassratio of gas turbine engine 20 may be greater than ten (10). In variousembodiments, geared architecture 48 may be an epicyclic gear train, suchas a star gear system (sun gear in meshing engagement with a pluralityof star gears supported by a carrier and in meshing engagement with aring gear) or other gear system. Geared architecture 48 may have a gearreduction ratio of greater than about 2.3 and low pressure turbine 46may have a pressure ratio that is greater than about 5. In variousembodiments, the bypass ratio of gas turbine engine 20 is greater thanabout ten (10:1). In various embodiments, the diameter of fan 42 may besignificantly larger than that of the low pressure compressor 44, andthe low pressure turbine 46 may have a pressure ratio that is greaterthan about (5:1). Low pressure turbine 46 pressure ratio may be measuredprior to inlet of low pressure turbine 46 as related to the pressure atthe outlet of low pressure turbine 46 prior to an exhaust nozzle. Itshould be understood, however, that the above parameters are exemplaryof various embodiments of a suitable geared architecture engine and thatthe present disclosure contemplates other gas turbine engines includingdirect drive turbofans.

In various embodiments, the next generation of turbofan engines may bedesigned for higher efficiency which is associated with higher pressureratios and higher temperatures in the HPC 52. These higher operatingtemperatures and pressure ratios may create operating environments thatmay cause thermal loads that are higher than the thermal loadsencountered in conventional turbofan engines, which may shorten theoperational life of current components.

In various embodiments, HPC 52 may comprise alternating rows of rotatingrotors and stationary stators. Stators may have a cantileveredconfiguration or a shrouded configuration. More specifically, a statormay comprise a stator vane, a casing support and a hub support. In thisregard, a stator vane may be supported along an outer diameter by acasing support and along an inner diameter by a hub support. Incontrast, a cantilevered stator may comprise a stator vane that is onlyretained and/or supported at the casing (e.g., along an outer diameter).

In various embodiments, rotors may be configured to compress and spin afluid flow. Stators may be configured to receive and straighten thefluid flow. In operation, the fluid flow discharged from the trailingedge of stators may be straightened (e.g., the flow may be directed in asubstantially parallel path to the centerline of the engine and/or HPC)to increase and/or improve the efficiency of the engine and, morespecifically, to achieve maximum and/or near maximum compression andefficiency when the straightened air is compressed and spun by rotor 64.

According to various embodiments and with reference to FIG. 1B, acombustor section 100 having a bypass flow duct 103 is provided. Bypassflow duct 103 is formed between an outer surface of combustor case 104and an inner surface of outer case 102. In various embodiments, one ormore cable conduits 200 are disposed within bypass flow duct 103 betweenthe combustor case 104 and the outer case 102. In various embodiments, aforward outer case cover 106 and an aft outer case cover 108 maycomprise a portion of outer case 102 and may be coupled to outer case102 by fasteners 110. In a like manner, a forward combustor case cover114 and an aft combustor case cover 116 may comprise a portion ofcombustor case 104 and be coupled to combustor case 104 by fasteners. Invarious embodiments and with brief reference to FIG. 2, cable conduit200 may be coupled to the forward outer case cover 106 and the aft outercase cover 108 at a head end 216 and may be coupled to forward combustorcase cover 114 and aft combustor case cover 116 at a foot end 218opposite the head end. In various embodiments, cables such as, forexample, igniter cables 112 pass through outer case 102 and combustorcase 104 via an interior volume of cable conduits 200 and are coupled atigniter coupling 122 to combustor 120. In various embodiments, a fansection, such as fan section 22, drives bypass flow 118 through bypassflow duct 103. In various embodiments, when bypass flow 118 encounters aforward face of cable conduit 200, bypass flow 118 tends to be dividedand separate around cable conduit 200 tending thereby to shed vorticiesand generate turbulence as the flow streamlines travel forward to aftalong the surface of the cable conduit. In various embodiments, and asillustrated in FIGS. 2, 3A, and 3B, a portion of bypass flow 118, maypass through a perforation 308 of a forward section 202 of a sleeve 205into an interior volume of the sleeve defined by the interior volume 310of the forward section 202 and the interior volume 312 of an aft sleeve306. The portion of bypass flow 118 may exit the interior volume of thesleeve at a perforation 316 in the aft sleeve 306 tending thereby toreduce or inhibit the generation of turbulence and vortices resultingfrom separation of the bypass flow 118 around cable conduit 200.

In various embodiments, and with additional reference to FIG. 2, a cableconduit 200 is provided. Cable conduit 200 has a head end 216 coupled toa sleeve 205 having a foot end 218 opposite the head end 216 and may besplit axially into one or more sections such as a forward section 202and an aft section 204. An outer case flange 210 having an upper surface212 is coupled at head end 216 and a boot 206 having a flange 208 iscoupled at the foot end 218. In various embodiments, outer case flange210 is coupled at upper surface 212 to an outer case of a bypass flowduct and boot 206 is coupled at flange 208 to a combustor case. Invarious embodiments, sleeve 205 extends from head end 216 relativelybeneath outer case flange 210 at an angle θ relative to upper surface212 of outer case flange 210. In various embodiments, outer case flange210 may have a cutout 220 penetrating into an interior of the cableconduit and filled with a split grommet 222 about an inner diameter ofcutout 220. In various embodiments, forward section 202 and aft section204 may be coupled by one or more straps 214. In various embodiments, asleeve such as sleeve 205 may comprise one of a circular cross section,an elliptical or oblate cross section, an angular cross section, ateardrop or airfoil cross section, or any other cross section tending tominimize aerodynamic disturbance and/or pressure loss in a bypass flow.In various embodiments, angle θ₁ may be between 90° and 45°, or may bebetween 80° and 55°, or may be between 70° and 65°.

In various embodiments, and with additional reference to FIGS. 3A and3B, a forward section 202 and an aft section 204 of a cable conduit 200are provided. In various embodiments forward section 202 may comprise aforward cap 300 having forward flange 340 comprising mounting features314 which may comprise nut plates 311. In various embodiments, forwardcap 300 may be coupled to a forward sleeve 304 defining an interiorvolume 310. In various embodiments, forward sleeve 304 may have aforward aerodynamic surface 330 comprising perforations 308 through theforward aerodynamic surface 330 and in fluid communication with interiorvolume 310. Forward section 202 may further comprise upper forward halfgrommet 318 a proximate forward flange 340 and lower forward halfgrommet 318 b proximate distal end 326 of forward sleeve 304. In variousembodiments, a forward half grommet, such as upper forward half grommet318 a or lower forward half grommet 318 b, may comprise a forward halfof a split grommet such as split grommet 222. In various embodiments, anupper surface of upper forward half grommet 318 a is substantially inplane with upper surface 334 of forward flange 340.

In a like manner, aft section 204 may comprise an aft cap 302 having anaft flange 338 comprising mounting features 314 which may comprise nutplates 311. In various embodiments, aft cap 302 may be coupled to an aftsleeve 306 defining an interior volume 312. In various embodiments, aftsleeve 306 may have an aft aerodynamic surface 332 comprisingperforations 316 through the aft aerodynamic surface 332 and in fluidcommunication with interior volume 312. Aft section 204 may furthercomprise upper aft half grommet 320 a proximate aft flange 338 and loweraft half grommet 320 b proximate distal end 328 of aft sleeve 306. Invarious embodiments, an aft half grommet, such as upper aft half grommet320 a or lower aft half grommet 320 b, may comprise an aft half of asplit grommet such as split grommet 222. In various embodiments, anupper surface of upper aft half grommet 320 a is substantially in planewith upper surface 336 of aft flange 338.

In various embodiments, a perforation such as perforation 308 orperforation 316 may comprise a hole not more than one eighth of an inch(⅛″) in diameter. In various embodiments, a perforation may comprise aslot, a channel, a hole, or any other suitable geometry. In variousembodiments, a sleeve such as forward sleeve 304 or aft sleeve 306 maycomprise one of steel, a stainless steel, or a titanium, or an alloy.

With additional reference to FIG. 4, a boot 206 of a cable conduit 200is provided. Boot 206 comprises a flange 208 and a flange washer 400having mounting features 416. An extrusion 402 defining an interiorvolume 404 of boot 206 extends relatively upward of flange 208 at anangle θ₂ relative to a plane defined by flange 208 and relativelyalternate to θ₁. In various embodiments, extrusion 402 may comprise agusset 410 and a circumferential channel 406 having a depth D beneathupper surface 412 of extrusion 402 into body material 414 of boot 206.In various embodiments, circumferential channel 406 may open at mouth408 which may comprise chamfer or fillet feature. In variousembodiments, depth D may be between one eighth of an inch (⅛″) [3.075mm] and four inches (4″) [101.6 mm], or may be between one inch (1″)[25.4 mm] and three and one half inches (3.5″) [88.9 mm], or may bebetween two inches (2″) [50.8 mm] and three inches (3″) [76.2 mm]. Invarious embodiments, a boot may comprise at least one of a rubber, asynthetic rubber, a silicone rubber, or a plastic.

In various embodiments, a circumferential channel such ascircumferential channel 406 may have a width substantially equal to athickness of a sleeve such as, for example, sleeve 205, forward sleeve304, or aft sleeve 306. In various embodiments, outer case flange 210 iscoupled at upper surface 212 to an outer case of a bypass flow duct andboot 206 is coupled at flange 208 to a combustor case with distal end326 of forward sleeve 304 and distal end 328 of aft sleeve 306 disposedwithin circumferential channel 406. In various embodiments, boot 206tends to allow forward section 202 and aft section 204 to translate,relative to the plane defined by flange 208, along the x-axis, they-axis, and the z-axis. In this regard, boot 206 tends to allow cableconduit 200 to be undisturbed by differential thermal growth betweenouter case 102 and combustor case 104.

With reference now to FIG. 5 and with additional reference to FIGS. 2,3A, and 3B, a split grommet 222 is provided comprising forward halfgrommet 318 and aft half grommet 320. In various embodiments, forwardhalf grommet 318 and aft half grommet 320 comprise an outer diameter500, an inner diameter 502, and a mating surface 506. In variousembodiments, inner diameter 502 further comprises a plurality of ribs504 extending radially inward of the inner diameter 502. In variousembodiments, aft half grommet 320 may be coupled at outer diameter 500to an aft cap or an aft sleeve such as, for example, aft cap 302 or aftsleeve 306 and, forward half grommet 318 may be coupled in a like mannerto a forward cap or a forward sleeve such as, for example, forward cap300 and forward sleeve 304. In various embodiments, a split grommet suchas split grommet 222 may comprise at least one of a rubber, a syntheticrubber, a silicone rubber, or a plastic.

In various embodiments, and with additional reference to FIG. 6, a splitgrommet 600 is provided. Split grommet 600 comprises features,geometries, construction, manufacturing techniques, and/or internalcomponents similar to split grommet 222 but with varied arrangement ofmating surfaces. Mating surfaces 602 comprises a compound curve 603defining a series of fingers 604 and pockets 606. When mating surfaces602 are disposed proximate each other, fingers 604 tend to interlockwith pockets 606 and, in response, tending to generate an interferencealong mating surfaces 602 thereby coupling the forward and aft half ofsplit grommet 600. In various embodiments, the interference along matingsurfaces 602 tends to resist radial pull force F₁.

In various embodiments, and with additional reference to FIG. 7, a splitgrommet 700 is provided. Split grommet 700 comprises features,geometries, construction, manufacturing techniques, and/or internalcomponents similar to split grommets 222 and 600 but with variedarrangement of mating surfaces. Mating surfaces 702 comprise cylindricalextrusions 704 and corresponding cavities 706 comprising bores 708opposite extrusions 704. Extrusions 704 comprise axial trenches 712defining interference surfaces 710. When mating surfaces 702 aredisposed proximate each other, extrusions 704 are disposed withincavities 706 and, in response, tending to generate an interferencebetween interference surfaces 710 and bores 708 in response therebycoupling the forward and aft half of split grommet 700. In variousembodiments, the interference between interference surfaces 710 andbores 708 tends to resist radial pull force F₂.

In various embodiments, and with additional reference to FIG. 8, a splitgrommet 800 is provided. Split grommet 800 comprises features,geometries, construction, manufacturing techniques, and/or internalcomponents similar to split grommets 222, 600, and 700 but with variedarrangement of mating surfaces. Mating surfaces 802 comprise taperedextrusions 804 and corresponding cavities 806 comprising bores 808opposite tapered extrusions 804. Tapered extrusions 804 compriseinterference surfaces 810 which taper from base 812 having a diametergreater than a diameter of bore 808 to tip 814 having a diameter lessthan the diameter of bore 808. When mating surfaces 802 are disposedproximate each other, tapered extrusions 804 are disposed withincavities 806 and, in response, tending to generate an interferencebetween interference surfaces 810 and bores 808 along a portion ofinterference surfaces 810 where the diameter is greater than thediameter of the bores 808 thereby coupling the forward and aft half ofsplit grommet 800. In various embodiments, the interference between theportion of interference surfaces 810 and bores 808 tends to resistradial pull force F₃.

In various embodiments, and with additional reference to FIG. 9, a splitgrommet 900 is provided. Split grommet 900 comprises features,geometries, construction, manufacturing techniques, and/or internalcomponents similar to split grommets 222, 600, 700, and 800 but furthercomprises embedded studs 904 protruding perpendicular to mating surfaces902. Embedded stud 904 comprises a conical head end 908 having a distaltaper 910 at the base of the head toward a shank 912 extending frombase. Shank 912 comprises a foot end 914 embedded in body material 918and having one or more flanges 916 about the shank opposite conical headend 908. Mating surfaces 902 comprise corresponding cavities 906,opposite embedded studs 904, defined by an outer mold line of conicalhead end 908 and comprising backwalls 920. When mating surfaces 902 aredisposed proximate each other, embedded studs 904 are disposed withincavities 906 and, in response, tending to generate an interferencebetween distal taper 910 and backwalls 920 thereby coupling the forwardand aft half of split grommet 900. In various embodiments, theinterference between the distal taper 910 and backwalls 920 tends toresist radial pull force F₄.

In various embodiments and with reference now to FIG. 10, a crosssection of a sleeve 1000 is shown. Sleeve 1000 comprises features,geometries, construction, manufacturing techniques, and/or internalcomponents similar to sleeve 205 of FIG. 2 but further comprises sleevelocking features. Forward sleeve 1002 comprises dimples 1004 inproximate mating surface 1018 in forward aerodynamic surface 1006located proximate mating surface 1018. Inner surface 1016 of dimple 1004protrudes radially inward of forward aerodynamic surface 1006 intointerior volume 1008. Aft sleeve 1010 comprises a recessed portion 1012set a distance relatively inward from aft aerodynamic surface 1022. Invarious embodiments, the inward distance of the recessed portion tendsto equal the thickness of the forward sleeve 1002. Recessed portion 1012comprises cups 1014 protruding into interior volume 1020 having an innersurface 1024 with a curvature tending to define a volume fitted to innersurface 1016 of dimples 1004. When mating surfaces 1018 are disposedproximate each other, inner surface 1016 of dimples 1004 tend to slideover recessed portions 1012 and drop into cups 1014 disposing, inresponse, inner surface 1016 proximate inner surface 1024 tending togenerate an interference between inner surface 1016 and inner surface1024 thereby coupling the forward sleeve 1002 to the aft sleeve 1010 andjoining interior volumes 1008 and 1020. In various embodiments, theinterference between inner surface 1016 and inner surface 1024 tends toresist radial pull force F₅.

In various embodiments and with reference now to FIG. 11, a crosssection of a sleeve 1100 is shown. Sleeve 1100 comprises features,geometries, construction, manufacturing techniques, and/or internalcomponents similar to sleeve 205 of FIG. 2 but further comprises sleevelocking features. Forward sleeve 1102 comprises tabs 1108 facingradially inward of forward aerodynamic surface 1126 at ends 1106.Channels 1110 are cut radially outward of interior volume 1112 towardforward aerodynamic surface 1126 along an axis of forward sleeve 1102relatively behind tabs 1108. Similarly, aft sleeve 1104 comprises tabs1109 facing radially outward of interior volume 1120 at ends 1114.Channels 1116 are cut radially inward of aft aerodynamic surface 1118toward interior volume 1120. When mating surfaces 1122 are disposedproximate one another, tabs 1108 and 1109 tend to slide over each otherand, in response, drop into channels 1116 and 1110 tending to generatean interference 1124 thereby coupling the forward sleeve 1102 to the aftsleeve 1104 and joining interior volumes 1112 and 1120. In variousembodiments, the interference 1124 tends to resist radial pull force F₆.

In various embodiments and with reference now to FIGS. 12A through E and13, a method 1300 of assembling a cable conduit is provided. In variousembodiments, method 1300 comprises step 1302, as shown in FIG. 12A, ofinserting igniter cable 112 through boot 206 and feeding igniter cable112 through outer case access port 1202 and combustor case access port1204 to igniter cable coupling 122. Igniter cable 112 is then coupled toigniter cable coupling 122 and boot 206 is passed down igniter cable 112and disposed within bypass flow duct 103. In various embodiments, method1300 comprises step 1304, as shown in FIG. 12B, of closing out combustorcase access port 1204 with forward combustor case cover 114 and aftcombustor case cover 116 by coupling forward combustor case cover 114and aft combustor case cover 116 to combustor case 104. Boot 206 iscontacted with the combustor case covers and mounting features 416 offlange washer 400 are aligned with corresponding features on the casecovers before boot 206 is coupled to forward combustor case cover 114and aft combustor case cover 116.

In various embodiments, method 1300 comprises steps as shown in FIG.12C, of inserting (step 1306) a forward section 202 and an aft section204 of a cable conduit into the mouth 408 of boot 206 and furtherinserting distal ends 328 and 326 downward into circumferential channel406 as indicated by arrows 1206. In various embodiments, upper forwardhalf grommet 318 a and upper aft half grommet 320 a of split grommet 222may be aligned with a ferrule or collet 1208 tending to dispose apredetermined length of igniter cable 112 within sleeve 205 which isformed (step 1308) as forward section 202 and aft section 204 arebrought into contact along the mating surfaces (referring to FIGS. 5through 11) and coupled about the igniter cable 112 as shown by arrows1210 to combine their interior volumes (referring to FIGS. 3A, 3B, 10,and 11, for example, interior volumes 310 and 312). In variousembodiments, step 1308 may further comprise coupling straps 214 aboutthe sleeve 205. In various embodiments and with additional reference toFIGS. 3A and 3B, method 1300 comprises steps as shown in FIGS. 12D and12E, of locating the cable conduit (step 1310) with respect to the outercase 102 by coupling forward flange 340 at upper surface 334 to forwardouter case cover 106 before securing the forward outer case cover 106 toouter case 102. After locating the cable conduit with respect to theouter case, outer case access port 1202 is closed by coupling forwardouter case cover 106 and aft outer case cover 108 to outer case 102 asindicated by arrows 1212 thereby coupling (step 1312) the cable conduitto the outer case 102.

Benefits, other advantages, and solutions to problems have beendescribed herein with regard to specific embodiments. Furthermore, theconnecting lines shown in the various figures contained herein areintended to represent exemplary functional relationships and/or physicalcouplings between the various elements. It should be noted that manyalternative or additional functional relationships or physicalconnections may be present in a practical system. However, the benefits,advantages, solutions to problems, and any elements that may cause anybenefit, advantage, or solution to occur or become more pronounced arenot to be construed as critical, required, or essential features orelements of the disclosures.

The scope of the disclosures is accordingly to be limited by nothingother than the appended claims, in which reference to an element in thesingular is not intended to mean “one and only one” unless explicitly sostated, but rather “one or more.” Moreover, where a phrase similar to“at least one of A, B, or C” is used in the claims, it is intended thatthe phrase be interpreted to mean that A alone may be present in anembodiment, B alone may be present in an embodiment, C alone may bepresent in an embodiment, or that any combination of the elements A, Band C may be present in a single embodiment; for example, A and B, A andC, B and C, or A and B and C. Different cross-hatching is usedthroughout the figures to denote different parts but not necessarily todenote the same or different materials.

Systems, methods and apparatus are provided herein. In the detaileddescription herein, references to “one embodiment”, “an embodiment”, “anexample embodiment”, etc., indicate that the embodiment described mayinclude a particular feature, structure, or characteristic, but everyembodiment may not necessarily include the particular feature,structure, or characteristic. Moreover, such phrases are not necessarilyreferring to the same embodiment. Further, when a particular feature,structure, or characteristic is described in connection with anembodiment, it is submitted that it is within the knowledge of oneskilled in the art to affect such feature, structure, or characteristicin connection with other embodiments whether or not explicitlydescribed. After reading the description, it will be apparent to oneskilled in the relevant art(s) how to implement the disclosure inalternative embodiment

Furthermore, no element, component, or method step in the presentdisclosure is intended to be dedicated to the public regardless ofwhether the element, component, or method step is explicitly recited inthe claims. No claim element is intended to invoke 35 U.S.C. 112(f)unless the element is expressly recited using the phrase “means for.” Asused herein, the terms “comprises”, “comprising”, or any other variationthereof, are intended to cover a non-exclusive inclusion, such that aprocess, method, article, or apparatus that comprises a list of elementsdoes not include only those elements but may include other elements notexpressly listed or inherent to such process, method, article, orapparatus.

What is claimed is:
 1. A gas turbine engine comprising: a compressorsection configured to compress a gas; a combustor section aft of thecompressor section and configured to combust the gas; a fan sectionconfigured to produce a bypass flow; an outer case having an innersurface and an inner case having an outer surface defining a bypass flowduct there between; and a cable conduit, disposed within the bypass flowduct, comprising: a head end, a sleeve having a foot end, a boot, and asplit grommet having a first upper surface, wherein the head end iscoupled to the sleeve opposite the foot end, wherein the boot comprisesa first flange and is coupled to the foot end, wherein the head endcomprises a second flange having a second upper surface and a cutoutpenetrating into an interior volume of the sleeve, wherein the splitgrommet is coupled about an inner diameter of the cutout, and whereinthe second flange is coupled at the second upper surface to the innersurface of the outer case and the first flange is coupled to the outersurface of the inner case.
 2. The gas turbine engine of claim 1, whereinthe cable conduit further comprises a forward section and an aftsection.
 3. The gas turbine engine of claim 2, wherein the forwardsection comprises a first perforation through a forward aerodynamicsurface and the aft section comprises a second perforation through anaft aerodynamic surface, wherein the first perforation and the secondperforation are in fluid communication with the bypass flow duct and theinterior volume of the sleeve, wherein a portion of the bypass flowpasses through the first perforation into the interior volume and exitsthe interior volume through the second perforation.
 4. The gas turbineengine of claim 3, wherein the boot comprises a circumferential channel.5. The gas turbine engine of claim 4, wherein the forward sectionfurther comprises forward sleeve having a first distal end and the aftsection further comprises an aft sleeve having a second distal end,wherein the first distal end and the second distal end are disposedwithin the circumferential channel.
 6. The gas turbine engine of claim5, wherein the boot tends to allow the forward section and the aftsection to translate in response to a differential thermal growthbetween the outer case and the inner case.
 7. The gas turbine engine ofclaim 6, wherein the sleeve comprises a sleeve locking feature.
 8. Thegas turbine engine of claim 6, wherein the split grommet comprises amating surface comprising at least one of an extrusion, a finger, acavity, a pocket, a bore, or an embedded stud.
 9. The gas turbine engineof claim 6, wherein the sleeve comprises at least one of a circularcross section, an elliptical cross section, an oblate cross section, anangular cross section, a teardrop cross section, or an airfoil crosssection.